As a method for producing difluoroacetic acid chloride, there have been known: (1) a method of chlorinating difluoroacetic acid with a chlorinating agent such as phosphorous pentachloride and the like; (2) a method for oxidizing 1,1-difluoro-2,2-dichloroethane (R-132a) with oxygen under temperatures and pressures (Patent Publication 1); and (3) a method for causing oxidation by irradiating a mixture of 1,1-difluoro-2,2-dichloroethane(R-132a), 02 and C12 with a high-pressure mercury lamp (Patent Publication 2).
Additionally, it has been known that difluoroacetic acid fluoride is obtained by subjecting 1-alkoxy-1,1,2,2-tetrafluoroethane to thermal decomposition in the presence of a metal oxide catalyst (Patent Publication 3).
Furthermore, in Patent Publication 4, there is disclosed that benzofluoride having a fluorine-containing substituent is fluorinated with calcium chloride thereby being converted into a corresponding benzochloride.